* gcse.c (gcse_constant_p): New function to identify constants

	suitable for constant propagation, including COMPARE with two
	integer constant arguments.
	(hash_scan_set): Use gcse_constant_p.
	(find_avail_set): Likewise.
	(cprop_insn): Likewise.
	(do_local_cprop): Likewise.
	(find_implicit_sets): Likewise.
	(find_bypass_set): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@65075 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7c438fa..266e9c7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2003-03-30  Roger Sayle  <roger@eyesopen.com>
+
+       * gcse.c (gcse_constant_p): New function to identify constants
+       suitable for constant propagation, including COMPARE with two
+       integer constant arguments.
+       (hash_scan_set): Use gcse_constant_p.
+       (find_avail_set): Likewise.
+       (cprop_insn): Likewise.
+       (do_local_cprop): Likewise.
+       (find_implicit_sets): Likewise.
+       (find_bypass_set): Likewise.
+
 2003-03-30  Matt Kraai  <kraai@alumni.cmu.edu>
 
        * except.h: Remove definition of varray_type.

diff --git a/gcc/gcse.c b/gcc/gcse.c
index f0e588e..d41a117 100644 (file)
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -572,6 +572,7 @@ static void hash_scan_set   PARAMS ((rtx, rtx, struct hash_table *));
 static void hash_scan_clobber  PARAMS ((rtx, rtx, struct hash_table *));
 static void hash_scan_call     PARAMS ((rtx, rtx, struct hash_table *));
 static int want_to_gcse_p      PARAMS ((rtx));
+static bool gcse_constant_p    PARAMS ((rtx));
 static int oprs_unchanged_p    PARAMS ((rtx, rtx, int));
 static int oprs_anticipatable_p PARAMS ((rtx, rtx));
 static int oprs_available_p    PARAMS ((rtx, rtx));
@@ -2155,6 +2156,25 @@ insert_set_in_table (x, insn, table)
     }
 }
 
+/* Determine whether the rtx X should be treated as a constant for
+   the purposes of GCSE's constant propagation.  */
+
+static bool
+gcse_constant_p (x)
+     rtx x;
+{
+  /* Consider a COMPARE of two integers constant.  */
+  if (GET_CODE (x) == COMPARE
+      && GET_CODE (XEXP (x, 0)) == CONST_INT
+      && GET_CODE (XEXP (x, 1)) == CONST_INT)
+    return true;
+
+  if (GET_CODE (x) == CONSTANT_P_RTX)
+    return false;
+
+  return CONSTANT_P (x);
+}
+
 /* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or
    expression one).  */
 
@@ -2178,7 +2198,7 @@ hash_scan_set (pat, insn, table)
       /* If this is a single set and we are doing constant propagation,
         see if a REG_NOTE shows this equivalent to a constant.  */
       if (table->set_p && (note = find_reg_equal_equiv_note (insn)) != 0
-         && CONSTANT_P (XEXP (note, 0)))
+         && gcse_constant_p (XEXP (note, 0)))
        src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
 
       /* Only record sets of pseudo-regs in the hash table.  */
@@ -2223,8 +2243,7 @@ hash_scan_set (pat, insn, table)
                    && REGNO (src) >= FIRST_PSEUDO_REGISTER
                    && can_copy_p [GET_MODE (dest)]
                    && REGNO (src) != regno)
-                  || (CONSTANT_P (src)
-                      && GET_CODE (src) != CONSTANT_P_RTX))
+                  || gcse_constant_p (src))
               /* A copy is not available if its src or dest is subsequently
                  modified.  Here we want to search from INSN+1 on, but
                  oprs_available_p searches from INSN on.  */
@@ -4015,7 +4034,7 @@ find_avail_set (regno, insn)
          If the source operand changed, we may still use it for the next
          iteration of this loop, but we may not use it for substitutions.  */
 
-      if (CONSTANT_P (src) || oprs_not_set_p (src, insn))
+      if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
        set1 = set;
 
       /* If the source of the set is anything except a register, then
@@ -4207,7 +4226,7 @@ cprop_insn (insn, alter_jumps)
       src = SET_SRC (pat);
 
       /* Constant propagation.  */
-      if (CONSTANT_P (src))
+      if (gcse_constant_p (src))
        {
           if (constprop_register (insn, reg_used->reg_rtx, src, alter_jumps))
            {
@@ -4328,8 +4347,7 @@ do_local_cprop (x, insn, alter_jumps, libcall_sp)
          if (l->in_libcall)
            continue;
 
-         if (CONSTANT_P (this_rtx)
-             && GET_CODE (this_rtx) != CONSTANT_P_RTX)
+         if (gcse_constant_p (this_rtx))
            newcnst = this_rtx;
          if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
              /* Don't copy propagate if it has attached REG_EQUIV note.
@@ -4611,7 +4629,7 @@ find_implicit_sets ()
            && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
            && GET_CODE (XEXP (cond, 0)) == REG
            && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
-           && CONSTANT_P (XEXP (cond, 1)))
+           && gcse_constant_p (XEXP (cond, 1)))
          {
            dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
                                         : FALLTHRU_EDGE (bb)->dest;
@@ -4733,7 +4751,7 @@ find_bypass_set (regno, bb)
        abort ();
 
       src = SET_SRC (set->expr);
-      if (CONSTANT_P (src))
+      if (gcse_constant_p (src))
        result = set;
 
       if (GET_CODE (src) != REG)